Ignition system for internal-combustion engines



March 23,1926. 1,577,670

L. M. WQOLSON IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed April 15 1924 l'rz'onel MWaOZSO-H Patented Mar." 1926.

' LIONEL 1r. wooLsoN, or nn'rnommrcmean, Assien'on 5 1,577,670 omen.)

T0 racmn moron can COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

) IGNITION' SYSTEM FOR I NTERNAL-COMBUSTION ENGINES.

Application med April 15, 1924. Serial No. 706,720.

To all whom it may concern} Be it known that I, LIONEL M. WOOLSON,

' a citizen of the United States, andresident drive, core, pole pieces, etc.

of Detroit, Wayne County, State of Michigan, have invented certain new and useful Improvements in Ignition Systems for Internal-Combustion Engines, of which the following is a specification.

This invention relates to internal combustion engines and to the ignition systems of such engines, and it has especial reference to the ignition apparatus of engines such as are used in the propulsion of 'aircraft. c

Among the chief requisites of engines of the character designated are reliability, and a high ratio of power to weight. In-the furtherance of the first of these characten is'tics, most aircraft engines are now equipped with double ignition, by which itis understood that each of the engine cylinders is provided with two spark plugs whichare supplied with electric energy from independent sources. By the use of such double systems, continuity of engine operation is insured, .as in the event of a fallure in one of the branches of the system the other branch would continue to supply ignition.

Certain parts of ignition apparatus of this character are of such a natureas to be practically indestructible and asthese parts are relatively hea it has been proposed to avoid the duplication thereof and thereby eflecta saving in weight. Accidents, seldom occur, for example, to such arts as the n theother hand, certain-parts such as the windings, condensers, interrupter's, etc., are necessar' and condensers, the latter constituting a pair of independent electrical circuits ar-- ranged in a common magnetic circuit provided bythe rotor, pole pieces and cores.

In the operation 0 'appiiratus of this kind it has been found that w mary coils becomes short 'circuit'ed, by reason of any accident. "such as the failure-of a condenser,- the inductiveefl'ect exerted on the other branch of the double system seriously interferes with the operation thereof,

en one .ofthe pri-' weakening the spark produced and-causing it to miss and to be otherwise erratic. This result obtains because the current induced in the healthy winding by the continuous and heavy flow of current in the short circuit winding, prevents the instantaneous collapse of the lines of force in the field when the interrupter opens. Since the induction of the high tension current in the secondary winding depends on such collapse of the lines of force, the 'high tension ignition current becomes weak and-irregular, as will be readily understoodby those skilled in this art.

It has been found that the inductive ef fectabove described may be greatly reduced, if notentirely avoided, by placing in series with the primary winding of the intake branch of sistance, preferably the former. The presence of such an inductance in the circuit does nothing toassist the ignition spark when the engine is operating on one branclronly,

however, and it does materially increase the arcing produced at the interrupter points.

One object of the present invention is to provide an internal combustion engine with the system, an inductance or rea double ignition system of the character described in which the effect of mutual inductance on each branch of the system shall be minimized and the ignition spark pro vided by either branch of the system shall be much improved, especially under ad-' verse conditions such as are caused by a short circuit of the other branch,

Another object of the invention is to prov de, means to reduce the inductive effect of' a short circuitcd primary in one-branch on the output of the other branch in such a manner as-not .tocause'excessive sparking atthe interrupter of either primary. Other objects of the invention will appear from the following description taken in connection with the drawings, which form a part of this'specification, and in which:

Fig. 1 is a schematic representation of an ignition system constructed in accordancewith this lnvention apphed to an internal combustion engine, showing the ignition control switch in one of its positions in ,full lings,"and in another position in dotted lines, an I v Figs. 2 and 3 are portionsof the system illustrated in Fi 1,- showing the switch respectively in 0t er positions.

. Referring to the drawing, at 10 is illusare pre rably integral with the engine crankcase 12. This crankcase is usually-a casting and on it are mounted the engine cylinders 13. The engine 10 is provided with the usual head 15 communicatln with the cylinders 13, in which are locate suitable spark plugs 14, there being two of the spark plugs 14 for each cylin er of the engine.

One of the spark plugs 14 in each of the cylinders is connected to one of the two electrically distinct branches A and B of the ignition system, each of which branches has a distributer 16, provided with a rotary arm 17 which is driven in timed relation to the engine in any ap ro'priate' manner (not shown). Each of t e arms 17 is connected by a suitable conductor 18 to one terminal of a high tension or secondary windingi 19, which forms a part of the correspon ing branch of the system. The other terminal of each of the windings 19 is grounded in terminate respectively in contacts a an able switch mechanism 28 the well known manner.

Corresponding to each of the secondary windings 19 is a low tension or primary winding 21, which windings are located in a common magnetic field with the windings 19 in the manner described. One terminal of each of the windings-21 is connected to a stationary contact point 22 of an interrupter or circuit breaker havin a pivoted arm 23, which carries a mova 1e contact point 24, and is operated by a cam 26 into and out of contact with the point 22 to make and break the circuit throu h the primary winding 21. The cam 26 is riven in timed relation to. the engine, as is'well understood. The pivoted arm 23 is connected to ground in the usual manner, and a condenser 27 is preferably connected across the contacts 22 and 24 to reduce the sparking at the surfaces thereof. i

The other terminals of the windings1 21,1 7 which are adapted to cooperate with suity which the operation of the ignition apparatus is controlled, and through which the primaryclrcuits of the branches A and B are completed.

Arranged adjacent the contacts a and b in spaced relation thereto, is a contact 29 which is connected b a suitable conductor with a direct groun tact 29 is arranged in spaced relation to the contacts a and b, and is adapted for connection to either one but not to both, so

that the primary circuit of either branch A or B may be completed directly. Any suitable mechanism may be employed to etfect this result. In the embodlment shown, the contacts a, b .and 29 are arranged on the arc of a circle, at the center 32 of which as at 31. This con-' is pivotally mounted an'arm 33 of the switch 28.. The outer end of the arm 33 is provided with contact members or blades 34 and 36, arcuate in form and spaced by a notch 37. These members 34: and 36 are thus disposedon the arc of the circle of the contacts a, b and 29. In the position shown in fulllines in Fig. 1, the contacts I) and 29 are connected, and circuitis completed through the branch B to the ground 31. In Fig. 2, the contact a is similarly connected. to contact 29, thev circuit of branch A being completed and that of branch B broken. The end of the arm 33, pivoted at 32, is connected by a suitable conductor 38 with a resistance 39, preferably of an inductive nature as shown, and the end of this inductance 39 is connected'to ground as at 41.

By moving the switch .arm 33 into the position shown in dotted linesin Fig. 1, it

is seen that the contacts a and bare conthe inductance 39 to ground at 41. In this position the branches A and B are arranged in parallel, and in series with the inductance 39, and this is the normal operating position. In this manner two sparks are provided in each of the cylinders from electrically independent sources. Should any accident occur to short circuit one of the primary windings 21, such as a failure of its condenser 27, the inductance 39 is in series with the other-winding 21, to minimize the inductiveelfect of the short circuited winding and to prevent the failure of the ignition. When it is desired to run on either of the branches A or B alone, the inductance 39 is removed from the circuit, which is'completed through the direct ground 31, so'that arcing at the contact points 22 and 24 is not unduly promoted.

Fig. 3, illustrates the position of the above may be used without departing from the spirit or scope of the invention.

What is claimed is: 1. The combination with an ignition system including a pair of windings, of switch A means adapted to control the flow of current through said windings and adapted for connection thereto either singly or together in parallel, and an inductance coil in series with the switch. c

2. The combination with an ignition system for internal combustion engines including a pair of windings, of switch means adapted to complete the circuit through either of said windings or through both said windings in parallel, and an inductance coil in series with the switch.

3. The combination with an ignition system for internal combustion englnes including a pair of windings, of switch means adapted to complete the circuit through either of the windings in two of its positions, and to complete the circuit of the'windings in parallel through an inductance coil in another position. i

4;. The combination with an ignition sys-" tem for internal combustion engines including a pair of windings, a current interrupter in each winding circuit adapted to connect oneend thereof to ground, a direct ground connection, an inductive ground connection, and switch means adapted to connect the other end of either winding to the direct ground connection and to connect the said ends in parallelto the inductive ground connection.

5. The combination in an ignition s stem for internal combustion engines having a pair of primary circuits including interrupters, of means to com lete either circuit or both circuits comprising terminals for the circuits, a direct ground, a switch arm, and an inductance coil in series with said arm and the ground, whereby either circuit terminal may be connected to the direct ground,

. and both terminals may be connected in parallel through said coil to ground.

6. The combination with an internal combustion engine, of a dual ignition system including electrically distinct circuits, means to directly complete either of the-circuits, and means to diminish the mutually inductive efiect of the circuits 'including an inductive resistance associated with the first named means and adapted to complete both said circuits;

7. The combination with an internal combustion engine having a dual ignition sys tem including windings arranged in a common magnetic field, o means connecting the windings in parallel to operate together, and means including an inductive resistance in series with the first named means to diminish the effect on either winding of a short circuit in the other winding.

8; The combination with an internal com mon magnetic field and each having an interrupter ofswitch means adaptedto complete the circuit-in either winding independently of the other and to complete the circuit in both windings in parallel, and means includingan inductive'resistanoe in series with the Switch means when the windings are connected ,in parallel.

9. The combination with an internal combustion engine having a dual ignition sys tem including windings arranged in a com mon magnetic field and each having an interrupter, of switch means adapted to complete the circuit in either winding independ ently of the other and to complete the circuit in-both windings in parallel, and means to prevent reduction in intensity of the current in one of said windings upon short circuit of the other winding, said means including aresistance in series with the switch means when the windings are in parallel.

10. The combination with an internal combustion engine, of. a dual ignition system having electrically distinct primary and secondary windings arranged in a common magnetic field and adapted for operation either independently or in unison, control.

means for the system including a switch adapted to complete the circuit through either primary winding independently of the other, and to connect the primary windings in parallel for operation in unison, and a resistance associated with the switch means connected in series with the primary wiilnilings when said windings are in para e 11. The combination with an ignition system including a; pair of windings arranged in a common magnetic field, of means including an inductlve resistance to limit the flow of current induced in either winding upon a. short circuit of the other winding.

12. The combination with an ignition system including a pair of windings arranged in a common magnetic field, of means to connect the windings for operation either singly or together, and an inductance in series with the other means when said windings are connected for operation together.

, 13.The combination with an ignition system including a pair of windings arranged m a common magnetic field, of a direct ground, means adapted to complete the circuit ofeither winding to said ground, and an inductive resistance adapted for connection in series with both said windings.

14. The combination with an ignition system having a pairof windings, of means including a resistance adapted to minimize the mutual inductive effect between. said windings. I

15. The combination with an ignition system having'a pair of windings, of means including a mesistance adapted to limit the formation of continuous currents in either of said windings.

ture.

LIONEL M. WOOLSON.

In testimony whereof I .atfix my signa- 

